Transducer holder



Jan. 10, 1950 w. s. ERWIN 2,494,433

TRANSDUCER HOLDER Filed June 6, 1946 Qnwutoz @157 ffzzazz- Patented Jam'lO, 1950 TRANSDUCER nommt poration oi Delaware Application June 6,1946. Serial No. 674,905

a I I The present invention relates to crystal holders and more specifically relates to holders for crystals used in measuring devices such as shown in my copending application Serial No. 532,199, Supersonic measuring means, filed April 21,1944, now Patent No. 2,431,233.

The measuring device shown in my copending application is used to determine certain physical characteristics of masses such as propellers, sheet metal and other regular or irregular shaped objects.

The problem of maintaining the piezoelectric crystal in satisfactory contact with the mass, the characteristics of which are being measured, is complicated by the irregular shaped surface of some of these masses, for example, airplane propellers. Crystal holders used prior to my present invention are satisfactory when used on masses. having fiat surfaces but are subject to some limitations when used on irregular shaped surfaces. These prior crystal holders are also of such construction as to present difficulty in replacing crystals as the entire holder must be disassembled to make replacements.

In my present invention the crystal is allowed freedom of movement so it may accommodate the most irregular shaped surface. This crystal is mounted so as to be readily removable without any disassembling whatsoever of the remainder of the holder.

It is the object of the present invention to produce a piezoelectric crystal holder that is simple in construction and convenient to use.

It is a further object of the present invention to produce a holder for a transducer which allows freedom of movement of the transducer.

1 Claim. (Cl. 171-327) 2 extended by means of a pigtail l2 to a connector IA. Connector I4 is adapted to be inserted in an electrical adapter It to permit conduction of electricity from that connector to a similar connector 24. The adapter I6 is rigidly secured concentric to the handle 2' by means of an insulating bushing Hi. This bushing is secured within a shell and prevented from axial movement by means of detents 22. The connector 24 has soldered thereto a spring 26 made from electrical conducting material. The other end of this spring is permanently secured to the crystal 30 which has a conducting electrode 3l. The crystal 30 has an in-' sulating bushing 28 rigidly secured thereto to prevent electrical contact between the crystal electrode and the shell 20. The spring 26 is the sole support and electrical connection to the crystal 30 and permits this crystal to have freedom of movement to secure the best'possible contact 20 between the crystal and the mass 32, the characthe mass 32.

. work as shown in the figure and additional pres- It is a still further object of the present invention to produce a crystal holder which is light in weight, simple in construction, allows freedom of movement of the crystal and permits interchange of crystals with a minimum of eiiort.

Other objects of the present invention will become apparent in the following specification and illustrated in the drawing and specifically pointed sure is applied on the handle to cause contact between the shell 2|] and the mass 32. The circult is then completed causing the electrical signal to be impressed upon the crystal and the resulting mechanical vibrations produced thereby transmitted to the mass 32.

The vibrations from the mass 32 are transmitted back to the crystal 30 and theelectrical signal produced thereby is introduced back into the circuit including the conductors 6 and 8. A preferred embodiment of my invention has been described but a large number of modifications thereof may be made without departing from the scope of this invention. For example, the conductors 6 and 8 may be of the standard two-wire type, or the outer conductor 6 may be omitted and the handle of the holder itself used as the conductor. I

It is to be understood also that although the invention has been described with specific refer,- ence to a particular embodiment thereof, it is i not to be so limited, since changes and alterations allow freedom 01' transducer movement and pre- 1 vent electrical shorting between said tubular member and said transducer.

a S. ERWIN.

PatentNo. 2,494,433

Certificate of Correction nummcns orrnn The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name 2,283,285 Pohlman May 19, 1942 2,410,193 Bach 2,431,233 Erwin 2,435,545 Rosenthal Feb. 3, 1948 Firestone Apr. 6, 1948 Januar 10, 1950 WESLEY S. ERWIN It is hereby certified that error appears in the printed specification of the above numbered patent requiring correction as follows: I Column 4, line 11, list of references cited, for thepatent number 2,435,545

and that the said Letters Patent should be read with this correction therein that the same may conform to the record of the case in the Patent Oflice.

Signed and sealed this 6th day of June, A. D. 1950.

THOMAS F. MURPHY,

Assistant Commissioner of Patents. 

